The present invention relates to the field of biological cellular cultures. More particularly, it relates to a novel apparatus and method for changing a liquid culture medium used to cultivate cell cultures with a new medium.
Changing culture medium is a routine and heavy job of isolated cell culture, and needs to be performed every other day. Traditionally, the procedures of changing culture medium include at least two separate steps:
1) Aspiration or removal of the old medium from a culture vessel by means of vacuum suction or pipetting; a process of dipping an open-ended tube into the liquid medium, and withdrawing the tube and liquid within the tube from the medium for disposal. PA1 2) Addition of new medium to the culture vessels using another tool, usually a pipette, to transfer medium from a liquid container to the culture vessels.
Generally, the process for the conventional operation of changing medium is described below. If using a vacuum means; aspirate the old medium, change the tool, draw the new medium, and release the new medium to the culture vessels. If pipetting; draw the old medium, dispose of it, draw new medium, and release the new medium to the culture vessels. The operator may or may not change pipettes to isolate the new medium from potential intermixing of residue from the old medium contained within the pipette.
These procedures involve many actions, multiple pauses, frequent opening of culture vessels and medium containers. Furthermore the potential exists for the prolonged exposure of cultured cells to air, particularly when a large volume of medium or a large number of vessels need to be changed. Therefore, the process is time consuming in the least and potentially harmful to the cultured cells due to their prolonged exposure to air as well as significantly increasing the risk of contamination due to the repetitive actions necessary.